Ok I have a fully forged bottom end 355 with stock L98 heads and a Comp Cams cam (.500/.510, 210/220 @ .050, 114 LSA) and a stock PROM.

I am running a P600B ATI ProCharger with a 12-14 psi pully (dont have a boost gauge yet) and 2 core intercooler.

I just put a set of SLP 1 3/4" headers on this weekend. Got my New Catco high flow Cats welded in and I hgave a BIG problem now.

My car lost ALL its top end. Everything. If I try to turn my FMU up higher it makes it worse. My car will bog, buck and shut down almost. I hook up my Scan Tool and it seems I'm running WAAY lean now. Instead of the optimal 900-960 mV on my o2 readings I'm at under 100. (Dont have a wideband o2, so sue me )

I have a set of Ford SVO 24 lb/hr injectors that were BARELY adequate for my setup with the stock manifolds on. I was blowing low 800's on my o2 sensor.

So I'm assuming that because my exhaust is scavanging so much better now then it was before that ALOT more air is able to enter the combustion chambers. That in turn makes my injectors way too small to squirt the right mix for my setup now. Does this sound right or am I talking out my a$$?

I am going to order a set of 36 lb/hr injectors anyway but will this be the fix?

The way my car is acting is EXACTLY the same thing it was doing when I first put on the blower on the stock engine with the stock 22 lb/hr injectors on there. Obviously putting the 24's on fixed it and for awhile I was able to get over 1 volt out of my o2 sensor at WOT.

What are your guys' opinions?

 

I would first make sure that you dont have any leaks and that you are getting the proper fuel pressure. If everything is good then i think the bigger injectors are the way to go.

 

<b>So I'm assuming that because my exhaust is scavanging so much better now then it was before that ALOT more air is able to enter the combustion chambers. That in turn makes my injectors way too small to squirt the right mix for my setup now. Does this sound right or am I talking out my a$$? </b>

I think your on the right track, in fact your probably damn close. But some other things to consider, like timing and fuel pressure are important too. Better scavenging means easier cooling and thus you should be able to run more timing. fuel pressure should go up alittle too, with bigger injectors i beleive thats the way to go. Good job, soon you will see a sizable increase in top end, once you get this straight! Headers are always a good mod!

 

Thanks for the input guys. I was very dissapointed after the install because all of my friends and myself were expecting HUGE gains since I was trying to run the amount of boost I am with Stock restrictive manifolds. Now that I have full exhaust I think I should be able to hit 115 mph traps once I get the injectors I need.

But maybe I should only go up to 30 lb/hr injectors? Is 36 too big for what I have now? I am going to upgrade my heads to worked AFR 190's in the next year. But maybe I should hold off 36's till then.

 

why dont u try burning a prom for it? youll be surprised how much there is to gain for a properly setup prom...

 

I need to get a cheap used laptop and a Diacom (my scan tool is limited) and then a burner and then an eraser and then learn how to do it right. Thats aLOT of work.

I will do that someday but when? I dont know.

 

I take it this setup isnt on the WS-6 then, arn't they ODBII instead of PROMS? In which case you could use a laptop and just use a program and interface and plug it in and do it yourself, skipping the erase / burning process....

 

i think hes referring to the suspension

heres part of his first post

 

They've had WS6 RPO codes since the 70's.

Its the 91 Formula with a WS6 suspension package. Thanks.